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Re: antenna rig and Lightning



My two cents worth.  

I have a fused disconnect box on my operating desk which opens everything
from the power mains with one throw of the knife switches.  I disconnect
all coax leads during bad weather.  I disconnect my modem (internal) from
the phone line and I unplug the PC at the wall socket.  HOWEVER, I forgot
about the rotor control cables.

We had a nearby strike to a tree, 75 feet behind the house, at the base of
which sat our neighborhood power distribution transformer for underground
service to the houses.  I have surge protectors at the power entrance to
the house.  We suffered no losses to anything in the house via the power
service while neighbors on both sides lost appliances such as ovens and
refrigerators, etc.  I lost a single chip in each of my TNC, digital clock
and serial port in the PC.  All of this damage was caused by induced
voltage in the connected rotor control cables.  There was no direct hit to
my antennas at all.  Now, I even unplug my KCT from the back of the rotor
control box.

This proved to me that nothing will save you like completely disconnecting
everything, even from a nearby hit.

Dave Metz wrote:
> 
> > X-To:          amsat-bb@AMSAT.Org
> > Reply-to:      <denniswj@hunterlink.net.au>
> > From:          "Dennis James" <denniswj@hunterlink.net.au>
> > To:            "saber electronics" <saber@vicksburg.com>, <amsat-bb@AMSAT.Org>
> > Subject:       RE: [amsat-bb] antenna rig and Lightning
> > Date:          Thu, 27 May 1999 10:40:29 +1000
> 
> > I have experienced a lightning strike on my antenna's and in my house, where
> > it completely damaged my radio gear, even finding its way to the fax machine
> > and video player.
> >
> > I agree with Phil on disconnecting all from antenna's and outlets.
> >
> > Get into the habit of disconnecting all antenna's and equipment from power
> > outlets( when not in use ), also your line to the telephone modem. Even when
> > there is no storms about as it's very easy to forget.
> >
> > Dennis De VK2DOR
> >
> 
> May I recommend another solution...  Like most of us with multiple radios and
> antennas, I don't (and most likely never will) disconnect all of my radio antennas
> during a storm.  If I did that liveing in Iowa, I'd wear the coax connectors out :-)!
> 
> Its been my experince that most damaging voltage spikes come in through the
> power line and telephone lines.  I suspect that the telephone is the worst offender.
> My entire station including the computers is connected to power through a
> single bladed disconnect switch (fused).  This is simple old fashioned safety.
> Remember the old ARRL "Switch to Safety" ads?
> 
> When the storms come up, I pull the switch and shut down the main bench.
> If you want more "automatic" protection, run your modem phone line through a
> DPDT relay with the relay coil activated by the 120VAC power.  Shutting the power
> off automatically disconnects the modem line, simple!
> 
> You can also run your feedlines through PolyPhaser surge suppressors to protect
> the antenna connections.  These are used on every commercial installation I have
> seen in my area.  Heavy braided ground connections and good ground rods will
> complete the installation.
> 
> Interestingly enought the local two meter repeater (with three antennas connected,
> UHF links, etc) stays on and connected through every storm.  It has never suffered
> any damage.  I keep expecting it, but it has not happened in 12 years.  It sits in my
> shack ten feet from my operating bench.  I must be lucky (or the
> repeater is)!
> 
> --73-- David WA0AUQ
> 
> ----
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-- 
73, Roy

Internet: w0sl@amsat.org
Home Page: http://home.swbell.net/rdwelch
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